"Kind of hard to see from here
"Kind of hard to see from here...
Do the engines have cylindrical shaped objects, about 18-24" long, and say 6-8" in diameter, with lots of hoses, mounted on top of or very near the engines?
If so, those are the heat exchangers (Hx). In automototive terms... the radiators. The only difference is instead of using the air flow across the fins of the radiator as the heat sink, they use raw water flowing inside the tubes of the Hx to carry the heat away from the engine coolant, which flows around the outside of the tubes... this is a closed loop system. One thing to note, it still depends on that raw water flow (open loop) for cooling. The raw water is sucked up by a small pump in the outdrive, and pumped through the Hx tubes, then out through the exhaust.
A purely open system has no Hx and sends the raw water through the engine to cool it.
If you still can't figure it out, send us a picture."
